Aspects of the present invention can relate to a display apparatus that generates a high-luminance and high-resolution image using plural projection type image display devices, and to an image information generating method adapted to the display apparatus. Related art projection type image display devices, such as a projector, have been receiving attention in recent years. The projection type image display device can be characterized by its high degree of freedom in display, such as a large display screen, the brightness of the display screen, and the ability to display an image on a curved surface. For example, it is possible to use plural projection type image display devices, so that projected images from the respective projection type image display devices are superimposed on a screen. This consequently enables a high-definition image to be formed on a larger screen.
Related art techniques to superimpose images on the screen using plural projection type image display devices are roughly divided into three types: “tiling projection”, “stack projection”, and the combination of these two types. The tiling projection can be chiefly characterized by the capability of generating an image on a screen can be luminance and resolution that become larger and higher in roughly proportion to the number of projection type image display devices used. The tiling projection, however, has problems as follows. That is, the image quality is deteriorated because joined portions are noticeable, colors become irregular due to individual differences of the projection type image display devices used, and further, it is difficult to display images at high definition while maintaining time synchronization.
Meanwhile, the stack projection can be chiefly characterized by its capability of generating a high-luminance image. The stack projection, however, also has problems as follows. That is, it is difficult to generate a high-resolution image, and precise position control is required. In addition, as with the tiling projection, it is difficult to display images at high definition while maintaining time synchronization.
The combination of the tiling projection and the stack projection has the characteristics and problems as described above. Although the combination of the tiling projection and the stack projection is not used as often as the tiling projection or stack projection alone, one example is disclosed, for example, in JP-A-2000-184317.
FIG. 20 is a view schematically showing the configuration of the example disclosed in the cited document. The example can include plural high-luminance and high-resolution projection type image display devices PJa, PJb, and PJc each covering an assigned projection region and a low-luminance and low-resolution projection type display device PJd covering the entire screen as a projection region.
Incidentally, projection regions formed on the screen by the individual projection type image display devices are essentially of a rectangular shape in any of the tiling projection, the stack projection, and the combination of the two types. This is because most of normally used projection type image display devices have rectangular projection regions.
When one image plane is formed using a combination of the projection type image display devices each having a rectangular projection region, it is preferable that the projection region formed by the projection type image display device is projected in a rectangular shape, which is the original shape of the projection region of the projection type image display device, or in a shape closer to the original shape.
Hence, in the projection mode in the related art using any of the tiling projection, the stack projection, and the combination of the two types, it is normal that a projection region from each of the projection type image display devices forming the apparatus is of a rectangular shape. In the cited document, too, the projection regions formed on the screen by the respective projection type image display devices are of a rectangular shape.
By specifying the projection regions from the respective projection type image display devices to be of a rectangular shape, which is the original shape of the projection region of the individual projection type image display devices, it is possible to achieve an advantage that values allocated to individual pixels of the respective projection type image display devices can be readily computed. In exchange, however, there is a problem that moiré (interference fringes) occurs particularly in a superimposed portion.
When projection regions of an original rectangular shape are superimposed intact, because pixels aligned in the form of a tetragonal lattice have the same size and periodic arrangement, interferences of pixels with respect to one another that gives rise to moiré are thought to occur readily.